Pulling irons can be embedded in concrete structures to provide a hook by which a crane or other moving device can grab and manipulate the structure. In the field, the pulling iron can also be used to attach a pulley for pulling cables or wires through a conduit into the structure using a winch. Such pulling irons can be confined to a recess formed in the concrete so as not to protrude past the wall of the structure.
A pulling iron pocket is used to form the recess in the concrete structure. A known pulling iron pocket is shown in commonly owned U.S. Pat. No. 4,443,980, which is incorporated herein by reference. A pulling iron is partially embedded in the concrete and projects through a slot in the pocket into the recess at the time the structure is poured. The conventional pulling iron pocket has a flat seal area for engaging a lid. It has been found that the flat seal area may not always provide a completely leakproof seal; and can allow some concrete slurry to seep into the pocket. Also, the slot through which the pulling iron is inserted into the pocket may not be adequately rigid to resist deformation under pressure, potentially permitting further leakage.
In use, after inserting the pulling iron through the slot, a user must support the pulling iron by measuring and cutting pieces of Styrofoam or the like and placing the pieces between the pulling iron hook area and the inside body of the pocket. Unfortunately, even when supported by Styrofoam or the like, the possibility of the pulling iron moving about inside the pocket is not eliminated. Thus, the pulling iron can become embedded too close to the inside edge of the recess, providing an inadequate clearance area for attaching a hook to the pulling iron.
To help support the pulling iron in the pocket and to reduce leakage of concrete slurry through the slot, a shield can be integrally formed with over-molding around the pulling iron, as shown in commonly owned U.S. Pat. No. 3,916,590 and the above referenced '980 patent. The integral shield rests against the slot in use. Although this innovation improved the situation, the pulling iron could still move about inside the pocket during pouring and some leakage through the slot continued to be noted. Another attempt to overcome the problem involves a snap system of small round bumps intended to attach an integral pulling iron shield to the slot. In addition, it has been attempted to add a neoprene gasket around the slot. However, these systems may not hold the iron in place well because the snaps are small, difficult to use and may not latch tightly. Adding neoprene is costly and does not eliminate leakage of concrete into the pocket if excessive deformation occurs around the slot.